The invention relates to a device for inspection of wafers for semiconductors. In particular, the invention relates to a device for detecting defects on the wafer surface, said device being disposed on a stage which can be displaced in two mutually perpendicular directions.
During the fabrication process in semiconductor production, wafers are sequentially treated in a multitude of process steps. With increasing integration density, the requirements on the quality of the structures formed on the wafers increase. To be able to check the quality of the structures formed and detect possibly present defects, corresponding requirement exists in terms of the quality, accuracy and reproducibility of the equipment components that handle the wafers. This means that in the position determination and reacquisition of the position after a special event, for example after a power outage, failure of the control software and/or emergency shut-down of the entire system, the stage that displaces the wafer in the two mutually perpendicular directions allows rapid and reliable readjustment.